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screen printing => Equipment => DIY - From master engineered marvels to cobbled together jury-rigged or Jerry-built junk! => Topic started by: IntegrityShirts on June 17, 2014, 04:58:09 PM
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Here she is, in all her glory. Ugly and not fully tidied up yet because I'm deciding whether to order some lower nm LED's and try them out.
- 600W computer power supply (overkill)
- 12V 30A automotive relays (2)
- Digital timer from Amazon (http://www.amazon.com/gp/product/B00DSQQSAE/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1)
- Heavy duty suction cups (http://www.amazon.com/gp/product/B00FJ3NRD0/ref=oh_details_o03_s00_i00?ie=UTF8&psc=1)
- (5) 5 meter rolls of 395-405nm 12V 5050 LED strip (non-waterproof if you can find it) (http://www.aliexpress.com/item/16-4ft-5M-UV-Ultraviolet-395nm-5050-SMD-Purple-300-LED-Flex-Strip-Light-12V-free/1699716645.html)
- 30"x18" sheet of aluminum sign material I had laying around
- L-bracket rods from Tractor Supply
Things I have learned so far:
- Chinese DC solid state relays suck.
- I didn't need as big a power supply as I bought.
- Soldering all those little tiny connections is a PITA
- Don't buy waterproof LED strips
I'm THINKING that I could get lower exposure times by going with a lower NM LED, such as a 365 or a 385nm range. Those are harder to source on Aliexpress and cost a bit more (~$200 for enough to do 1 23x31 exposure unit).
Results so far were carried out with Aquasol HVP AND SP1400.
150S with a 1/2 coat round edge Aquasol HVP is right at 30 seconds for a good exposure
135S with a 2/3 coat round edge Aquasol HVP is around 50 seconds
200S with a 1/1 coat round edge SP1400 is around 90 seconds
110 yellow mesh (murakami) with a 2/2 round edge SP1400 should be around 110 seconds
PICS!
(https://lh6.googleusercontent.com/-aNSUozVTBiY/U6CdmU7k6sI/AAAAAAAAHDg/bl4gFUVFNHs/s1600/IMG_20140617_154921.jpg)
(https://lh4.googleusercontent.com/-X5kL_QyEpxY/U6CdobH-CjI/AAAAAAAAHDo/wW6cdI195Io/s1600/IMG_20140617_154946.jpg)
(https://lh4.googleusercontent.com/-TF55zPCIKeo/U6CdtjB1kZI/AAAAAAAAHEA/2wGe6kYvw5M/s1600/IMG_20140617_155003.jpg)
(https://lh4.googleusercontent.com/-IThrvrcRfX8/U6CdqHmvsWI/AAAAAAAAHDw/pK844ByIVgk/s1600/IMG_20140617_155039.jpg)
There are a few rows where I peeled the waterproof goop coating off the LEDs to see if it made a hot spot (it didn't)
(https://lh5.googleusercontent.com/-2H6tCQQ7kSw/U6Cdrz7B30I/AAAAAAAAHD4/njyc-QSuUj8/s1600/IMG_20140617_155121.jpg)
This is a 200S 1/1 round edge sp1400 @ 90 seconds
(https://lh5.googleusercontent.com/-bvTnjETEBn8/U5oXvI_uGAI/AAAAAAAAG70/ah3kN3owXTc/s1152/IMG_20140612_170723.jpg)
This is a 200S 1/1 round edge sp1400 @ 90 seconds
(https://lh6.googleusercontent.com/-y3WwkFKnOBI/U5oX9EGXlII/AAAAAAAAG7k/PV8qrCXRffU/s1152/IMG_20140612_170558.jpg)
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That is AWESOME!!!!!
So all in what did it run you?
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Bravo!!!! that is a super cool DIY
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Pretty slick, you have way too much free time on your hands.
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I bet you could sell the "plans" for that for $29.95... I'd buy one!
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Pretty slick, you have way too much free time on your hands.
You're right! I get obsessed with little projects like this. It was probably Pierre saying that he wouldn't recommend anyone try a DIY set up. I always like a challenge.
Nah not going to sell plans. I'll answer any questions if people want to build their own!
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That is so cool.
What is your LPI in the photo?
Unbelievable.
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Pretty slick, you have way too much free time on your hands.
You're right! I get obsessed with little projects like this. It was probably Pierre saying that he wouldn't recommend anyone try a DIY set up. I always like a challenge.
Nah not going to sell plans. I'll answer any questions if people want to build their own!
I have been proven wrong many a time! This looks like a fun and worthwhile project!
The only thing I'd add is getting a UV meter and measuring the uniformity of the light. They can be had on ebay for $150 or so.
Pierre
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That is so cool.
What is your LPI in the photo?
Unbelievable.
That's the 65LPI row of the kiwo exposure calculator.
Thanks Pierre. It could be better in a Version 2. I was hoping for Starlight level results, but in the end it's about the same as my 5k Olec. UV meter is probably not a bad idea. If it were accurate enough to see if my row spacing is correct. Still thinking a lower UV range LED might be the ticket to a hotter exposure. Or maybe even a blend of two different UV range strips in an alternating row setup.
I think I'm at about $250 investment. The goal here, worst case, was to have a usable backup in case the 5k Olec breaks. Best case it would replace the Olec. Right now I'm using it for all screens and will continue to play with timing and see how the screens hold up to waterbased with the SP1400 and no other treatment/hardeners. I don't typically do long run WB/discharge, largest is around 250 pieces coming up next week, but I'll give it a go and should at least be able to see some break down or softness at the end if it's a bad exposure.
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$250!? That is great! You sir are my new hero this week!!
I'm not sure 100% if all the LED units on the market have multiple UV range(Pierre would know for sure) but I know the "Light Speed" unit doors have 2 different ranges, and the creator claims that was key.
What do you want to bet your little DIY project has a effect on commercially available units? :)
Again, awesome job!
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That is so cool.
What is your LPI in the photo?
Unbelievable.
That's the 65LPI row of the kiwo exposure calculator.
Thanks Pierre. It could be better in a Version 2. I was hoping for Starlight level results, but in the end it's about the same as my 5k Olec. UV meter is probably not a bad idea. If it were accurate enough to see if my row spacing is correct. Still thinking a lower UV range LED might be the ticket to a hotter exposure. Or maybe even a blend of two different UV range strips in an alternating row setup.
I think I'm at about $250 investment. The goal here, worst case, was to have a usable backup in case the 5k Olec breaks. Best case it would replace the Olec. Right now I'm using it for all screens and will continue to play with timing and see how the screens hold up to waterbased with the SP1400 and no other treatment/hardeners. I don't typically do long run WB/discharge, largest is around 250 pieces coming up next week, but I'll give it a go and should at least be able to see some break down or softness at the end if it's a bad exposure.
most LEDs come with a 120 degree lens. Assuming light distribution is conical round rather than elliptical, spacing between the rows should match the spacing between the elements on the strips. Otherwise you'd have hot spots. With a meter you should be able to change the distance up and down until you get even light readings. If you are hot above the LED the glass needs to be further and if you are hot between the element move the glass closer.
here's a nice timer for anybody looking to try building one of these:
http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368 (http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368)
(sorry, just found this last night)
I think alternating strips of different wavelengths would introduce the effects similar to hot spots as you would have different penetrating and crosslinking ability between the strips. It might be worth contacting a manufacturer in China and asking them to make strips with three different wavelengths on them (5050 strips have LEDs with three sources in each LED and can be made with RGB so it might be possible to put three different wavelengths in each unit. The problem is, all the lower nm LEDs I've seen are significantly lower Wattage than the 395-405nm).
from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
(http://www.ulano.com/images/exposure/chart1.jpg)
pierre
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those are some awesome results... very impressed... kinda glad I didn't see this before I bought our new unit here, as i'm happy to have at least one part of the shop that i'm not continually tinkering with. :)
I highly doubt that we'll see any price reduction in the LED units for a while.. heck, the Starlight 2331 costs less than a 3140 MH unit...
I was under the impression that M&R did testing to understand the light diffusion pattern from the led strips and then matched the height of the glass so that it was perfect coverage with as minimal of undercutting as you can get having multiple lights.
I can tell you that looking at the strips on our uniit, there's a perfect square between each and every 4 lights...
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Now keep in mind, your hero status with me is good for a period of 1 week. That being said, in my most intelligent and influential Pierre voice/post- "it would be nearly impossible and unlikely someone could make a D.I.Y. DTS unit." Now some may call that a challenge.....:D;)
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Now keep in mind, your hero status with me is good for a period of 1 week. That being said, in my most intelligent and influential Pierre voice/post- "it would be nearly impossible and unlikely someone could make a D.I.Y. DTS unit." Now some may call that a challenge.....:D;)
In the first couple years of DTG the same challenge was issued and many "experts" explained why it was impossible for a DIY DTG. Sure enough people started making them and some were pretty decent to boot.
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Now keep in mind, your hero status with me is good for a period of 1 week. That being said, in my most intelligent and influential Pierre voice/post- "it would be nearly impossible and unlikely someone could make a D.I.Y. DTS unit." Now some may call that a challenge.....:D;)
In the first couple years of DTG the same challenge was issued and many "experts" explained why it was impossible for a DIY DTG. Sure enough people started making them and some were pretty decent to boot.
just for the record, I am not an expert (hell, 99% of the ppl here have more printing experience than I do) and I did not say it could not be done, just that I would not recommend it (due to proper light alignment being so critical). UV light meter turns out to be a lot cheaper than expected and easier to get. It will still take patience, steady hand and some basic geometry to get it done right. My assumption is that most ppl would just put the strips down and consider it done which can lead to some rather big problems. Unit done here is only few hours away from being a top notch solution.
Here's the link to the UV meter I picked up:
http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_sop=15&_nkw=UV513AB&rt=nc&LH_BIN=1 (http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_sop=15&_nkw=UV513AB&rt=nc&LH_BIN=1)
pierre
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Pierre you are so concerned about not being a expert, can you just please make an official challenge for a D.I.Y. DTS already!? :P
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most LEDs come with a 120 degree lens. Assuming light distribution is conical round rather than elliptical, spacing between the rows should match the spacing between the elements on the strips. Otherwise you'd have hot spots. With a meter you should be able to change the distance up and down until you get even light readings. If you are hot above the LED the glass needs to be further and if you are hot between the element move the glass closer.
here's a nice timer for anybody looking to try building one of these:
[url]http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368[/url] ([url]http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368[/url])
(sorry, just found this last night)
I think alternating strips of different wavelengths would introduce the effects similar to hot spots as you would have different penetrating and crosslinking ability between the strips. It might be worth contacting a manufacturer in China and asking them to make strips with three different wavelengths on them (5050 strips have LEDs with three sources in each LED and can be made with RGB so it might be possible to put three different wavelengths in each unit. The problem is, all the lower nm LEDs I've seen are significantly lower Wattage than the 395-405nm).
from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
([url]http://www.ulano.com/images/exposure/chart1.jpg[/url])
pierre
Yes, most all these strip LED's claim 120 degree lens. I did try to lay them out "square" meaning they'd have equal distance between rows and columns.
While I do think a 5050 with 3 different wavelength leds would be the best, I don't think anyone is currently using that setup. In fact, I'd be willing to bet that the starlight uses all the same LED's at the same wavelength. Wouldn't it be easy to tell by reading the resistance value off the strip's resistors? That would net us the voltage to the LED's and give us a good guess that they're all the same. The 395nm range have 270ohm resistors. What's the starlight use?
Distance from the glass is definitely something a UV meter might help determine IF its sensor is small/narrow/focused enough to pinpoint a change within a few nudges across the top of the glass when taking readings.
When I chose the 395nm range, I used this article from screenweb (http://"http://www.screenweb.com/content/taking-control-screen-exposure") to form my "opinion" on what range would work best for a cheapie diazo emulsion.
If those charted images are accurate, lowering down to a 365nm LED, should yield LONGER diazo times and shorter Photopolymer times, right?
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May be the best DIY tool ever shared on this site. Simply amazeballs.
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Well hell who do you guys think build this stuff aliens ;D ppl build this stuff and with the right tools DIY almost has no limit...might be ugly but works. I LIKE it!!!!!! good job IntegrityShirts
Darryl
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most LEDs come with a 120 degree lens. Assuming light distribution is conical round rather than elliptical, spacing between the rows should match the spacing between the elements on the strips. Otherwise you'd have hot spots. With a meter you should be able to change the distance up and down until you get even light readings. If you are hot above the LED the glass needs to be further and if you are hot between the element move the glass closer.
here's a nice timer for anybody looking to try building one of these:
[url]http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368[/url] ([url]http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368[/url])
(sorry, just found this last night)
I think alternating strips of different wavelengths would introduce the effects similar to hot spots as you would have different penetrating and crosslinking ability between the strips. It might be worth contacting a manufacturer in China and asking them to make strips with three different wavelengths on them (5050 strips have LEDs with three sources in each LED and can be made with RGB so it might be possible to put three different wavelengths in each unit. The problem is, all the lower nm LEDs I've seen are significantly lower Wattage than the 395-405nm).
from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
([url]http://www.ulano.com/images/exposure/chart1.jpg[/url])
pierre
Yes, most all these strip LED's claim 120 degree lens. I did try to lay them out "square" meaning they'd have equal distance between rows and columns.
While I do think a 5050 with 3 different wavelength leds would be the best, I don't think anyone is currently using that setup. In fact, I'd be willing to bet that the starlight uses all the same LED's at the same wavelength. Wouldn't it be easy to tell by reading the resistance value off the strip's resistors? That would net us the voltage to the LED's and give us a good guess that they're all the same. The 395nm range have 270ohm resistors. What's the starlight use?
Distance from the glass is definitely something a UV meter might help determine IF its sensor is small/narrow/focused enough to pinpoint a change within a few nudges across the top of the glass when taking readings.
When I chose the 395nm range, I used this article from screenweb (http://"[url]http://www.screenweb.com/content/taking-control-screen-exposure[/url]") to form my "opinion" on what range would work best for a cheapie diazo emulsion.
If those charted images are accurate, lowering down to a 365nm LED, should yield LONGER diazo times and shorter Photopolymer times, right?
that's funny, as I was looking for that article this morning to reference it and could not find it. It shows the curves for both the penetration and sensitivity unlike the other graphs out there.
In a quick recap it states the light should be 360-390 for SBQ and 390-420 for Diazo.
I think 365-380-410 would probably be the best to cover all the possibilities. According to the article, you should be golden with the Diazo!
Yes, the measuring portion of the UV meter is rather small, about the size of one LED, so you should be able to dial it in rather nicely!
pierre
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that's funny, as I was looking for that article this morning to reference it and could not find it. It shows the curves for both the penetration and sensitivity unlike the other graphs out there.
In a quick recap it states the light should be 360-390 for SBQ and 390-420 for Diazo.
I think 365-380-410 would probably be the best to cover all the possibilities. According to the article, you should be golden with the Diazo!
Yes, the measuring portion of the UV meter is rather small, about the size of one LED, so you should be able to dial it in rather nicely!
pierre
Yeah I kinda went into this with that article as a basis for my LED choice, not so sure that was a good idea or whether it is truly accurate across all diazo/photopolymer emulsions.
After some more testing of exposure times vs. emulsion thickness, I'm not so sure these LED's are the best solution. They just don't seem bright enough to fully penetrate the emulsion in a timely manner. By timely I mean faster than my 5k watt Olec. If the emulsion is a thicker coating it is PAINFULLY slower than the Olec to get a full exposure. You can see the outline of the film pretty well which tells me not nearly enough light got through to the squeegee side.
I knew going into this project that the LED choice was going to be the hurdle, as the rest is easy wiring. Think I'll request a couple samples from different manufacturers to do some more testing, which will delay a true verdict for a while.
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UPDATE with new LEDs and power supply!
I opted to order some more chinese 395nm LED strips and power them at opposite ends and power EACH row individually to avoid voltage drop on the thin strip material. Then, to further avoid voltage loss, I bought an adjustable power supply to pump these up to 13.8V to make sure they weren't thirsting for voltage.
The results? Well, pretty much the same: 150S with a 1/2 coat round edge Aquasol HV is right at 40 seconds for a good exposure.
Is it a good exposure? Yes, on Aquasol HV, it's a good solid exposure similar to 40 light units on the Olec 5k.
Is there some undercutting? Yes, a little. I need to move the LEDs closer to the glass but have to clearance some of the wiring loom at the ends to get them up higher which I think will reduce the undercutting.
Are these the best LEDs? NO. I'm not sure you can reliably get chinese UV LEDs that perform as indicated. It's a crap shoot.
(https://lh6.googleusercontent.com/-Ci4A_EIem0g/VHzNsU0AlBI/AAAAAAAAKGM/1hjFj6zWf_w/s1600/DSC_0067.JPG)
(https://lh4.googleusercontent.com/-dtU_KqyZkHw/VHzNtzkwU2I/AAAAAAAAKGQ/VlD0OERf_sY/s1600/DSC_0068.JPG)
(http://hhttps://lh5.googleusercontent.com/-ehVdPAqNGug/VHzNvuPuPNI/AAAAAAAAKGc/2oZs1lF-oNQ/s1600/DSC_0069.JPG)
(https://lh5.googleusercontent.com/-etDDm4EPMrw/VHzNxDksQBI/AAAAAAAAKGo/YkhcUkUjRLI/s1600/DSC_0070.JPG)
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I have the same DMM.
Barring more sophisticated test equipment have you thought of using the photocell from you Olec integrator
to compare output? Obviously the two light sources would be measured differently but you'd at least have a comparison.
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Nice.... well done. If the exposure time is the same, I'd be tempted to dial back the voltage.
When I turned up the voltage on mine, they got pretty warm & that's the number one cause of failure (overheating of the internal diode joint).
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from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
([url]http://www.ulano.com/images/exposure/chart1.jpg[/url])
pierre
Am I reading this wrong or wouldn't the 350nm be just the perfect wavelength for everything? (if you had to pick just one) It hits SBQ at 87%, Fe+++(whatever that is) at 52% (not great but WAY better than 5% that the 405nm hits it at), Diazo at 93% and Diazo/AC (whatever that is) at 70% (again, better than 45% that the 405 hits it at).
If you had to pick ONE wavelength what would it be?
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I don't think that chart is accurate given what abuffington has posted since this thread started.
I was originally trying to figure out which wavelength to buy but I think the quality of the Led is just as important.
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from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
([url]http://www.ulano.com/images/exposure/chart1.jpg[/url])
pierre
Am I reading this wrong or wouldn't the 350nm be just the perfect wavelength for everything? (if you had to pick just one) It hits SBQ at 87%, Fe+++(whatever that is) at 52% (not great but WAY better than 5% that the 405nm hits it at), Diazo at 93% and Diazo/AC (whatever that is) at 70% (again, better than 45% that the 405 hits it at).
If you had to pick ONE wavelength what would it be?
that chart is only half of the picture (go figure!). Turns out there is penetration and activation. First one has something to do with how well the light gets through and the other is what light activates the best. They are quite a bit apart and it seem the best spot (in between both) is in the 385 or so range for most emulsions. I'll see if I can dig up the other chart.
pierre
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from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
([url]http://www.ulano.com/images/exposure/chart1.jpg[/url])
pierre
Am I reading this wrong or wouldn't the 350nm be just the perfect wavelength for everything? (if you had to pick just one) It hits SBQ at 87%, Fe+++(whatever that is) at 52% (not great but WAY better than 5% that the 405nm hits it at), Diazo at 93% and Diazo/AC (whatever that is) at 70% (again, better than 45% that the 405 hits it at).
If you had to pick ONE wavelength what would it be?
that chart is only half of the picture (go figure!). Turns out there is penetration and activation. First one has something to do with how well the light gets through and the other is what light activates the best. They are quite a bit apart and it seem the best spot (in between both) is in the 385 or so range for most emulsions. I'll see if I can dig up the other chart.
pierre
OK, read this:
http://www.screenweb.com/content/tips-optimum-screen-exposure (http://www.screenweb.com/content/tips-optimum-screen-exposure)
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Yeah I keep re-reading that article over and over again haha. Well, if anyone out there wants to try this project, I'd suggest going with a 385nm or lower LED strip to see how it compares to the 395nm strips North and I have already tested with similar results. I have a feeling the 10nm lower strips might be the ticket to a quicker complete exposure.
If I can source a non-shady supplier, I may give it another go here this month as it is the slow season now.
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I know this has been discussed here and there, but I would love to start a comprehensive thread about these DIY LED builds with standard formatting and an updated first post with details of each build and some kind of consensus summary. After the new year I think I am going to try my own build and would like to further the development and discussion rather than rehash others mistakes and what not.
Can you detail the following in this format, and note after each what you might change or like to see tried for comparison:
LED Details:
-Source
-Cost (in total/per LED/shipping/etc)
-Wavelength (and any other details related to the light output itself)
-Electrical requirements/wiring diagrams, etc.
Build Details:
-Overall Size
-LED Layout (distance between bulbs,distance from glass, etc)
-Glass (thickness, type, source, etc)
-Peripheral info related to vacuum blanket, etc
Film/Emulsion/Exposure Details:
-Type of emulsion and coating technique
-Film brand and printer output
-Exposure Times and mesh used
Random thoughts, what you would improve, etc:
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I know this has been discussed here and there, but I would love to start a comprehensive thread about these DIY LED builds with standard formatting and an updated first post with details of each build and some kind of consensus summary. After the new year I think I am going to try my own build and would like to further the development and discussion rather than rehash others mistakes and what not.
Can you detail the following in this format, and note after each what you might change or like to see tried for comparison:
LED Details:
-Source
-Cost (in total/per LED/shipping/etc)
-Wavelength (and any other details related to the light output itself)
-Electrical requirements/wiring diagrams, etc.
Build Details:
-Overall Size
-LED Layout (distance between bulbs,distance from glass, etc)
-Glass (thickness, type, source, etc)
-Peripheral info related to vacuum blanket, etc
Film/Emulsion/Exposure Details:
-Type of emulsion and coating technique
-Film brand and printer output
-Exposure Times and mesh used
Random thoughts, what you would improve, etc:
I agree with everything you're saying. BUT, this is still a work in progress and I don't really want to post anything as fact until we can reach a consensus on all the components. The biggest variable here is the LED type.
BUYER BEWARE - LED's are vastly mis-represented on the internet with no way of actually knowing what you're getting until you get it. There are no markings or part numbers on these led chips so you have to choose reputable seller and hope they send you the right stuff!
That being said. I have been in contact with an alibaba supplier for UV strips and his PDF catalog he attached sheds a little light on the subject, or literal lack of light...
He lists 3 categories of strip, all the same in specification:
5050 SMD UV LED 60 LED per meter, 5m rolls
The differences in the 3 categories??? Power consumption! 4.8w/m, 7.2w/m, 14.4w/m. A lot of suppliers, MOST in fact, list their LED's as 14.4w/m for a 5m roll. Now, Gilligan or North, have you measured the amperage draw of your strips? I'm willing to bet my strips don't pull 72w per 5 meters or my power supply would be overloaded immediately on start up. I'll see if I can measure one row with my cheapy multimeter and calculate actual load.
What I THINK we need either the 365-370nm range strips, or 380-385nm like Pierre suggested. There is a HUGE price jump between these two ranges and both are 3-4 times the cost of 395nm strips. The idea here is to get the times down into the starlight range, to actually make these DIY setups WORTH the effort to source and assemble. If it ends up costing $700 instead of $200 and you get starlight performance, it's worth it in my opinion.
All this being said. It would probably be easier to mimic the light setup of the vastex style led's over the strip style as there are fewer options in those larger power LED's. I'm not going down that path now though. Too much invested in this project.
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I don't have a uv strip but a white strip.
I think all my meters have blown fuses, I'll have to double check. So no way to tell DC amp draw.
According to an online calculator I found it's suggesting that based on what the psu was drawing from the wall (minus it's idle draw) I'm just under 5 amps.
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Just did a load test for one row (45 LED) and at 12V it draws .56 amps. Doing a little math to calculate total watts per roll vs what is advertised for this strip:
Specs: 72W per 5m roll
Actual: 44.8W per 5m roll
So TOTAL power is 201.6W when in reality they SHOULD be 324W.
I'm requesting some samples from a different alibaba seller in 365-370nm and 380-385nm. If I can get a roll of each I can make a mini exposure grid big enough to test the exposure calculator area of a screen and I can also load test each strip to verify they are high current LED's.
As an idea of cost...
Enough LED's to make a 380-385nm unit runs $650
Enough LED's to make a 365-370nm unit runs $1550
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What is your math behind that conversion?
Where are you measuring your .56 amps from?
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Each row of my grid has 45 LED's. I disconnected one row and measured amperage draw while only powering that row. That equals .56amps @ 12V (I lowered the power supply down to 12V for this test)
Easier to google an image of how I hooked it up than explain it haha:
(http://www.cdn.sciencebuddies.org/Files/4808/6/fig7_multimeter-series-measure-current.jpg)
.56/45 = .01244amps per LED
300 x .01244 = 3.7333amps per "roll" LED (300 LEDs per roll)
amps x volts = watts:
3.7333 x 12 = 44.8watts
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Ok, cool... that is of course the correct way.
Interesting. I wonder if they are rated at "burst" power?
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Has anyone tried buying the LED's from reputable places here in the states? Then you don't have to worry about getting the right nm. I was given these names as reputable trustworthy outlets - Arrow, Avnet, and Degikey.
I talked to my dad about this who is retired now, he was head of purchasing for a company that imported millions of LED's dating back maybe 25 years. They eventually ended up having 3 or 4 factories of their own in China and he was the main go between from US to China and vise versa. Anyway, when I asked him about a connection or lead in China he said for the most part it is a crap shoot unless you are going to be moving $100K+. What they say and advertise for nm is not necessarily what is going to ship, for a number of reasons. The places in the states may be more expensive but they have the buying power and discerning customer base that requires accuracy. Just a thought, eliminate one variable from the equation...
Side note, it was pretty cool my first exposure unit(which we still have) is from Workhorse and when I bought it we found components in it from the company my dad worked for, pretty cool. I also think I've seen their components on damn near all the new M&R autos. Funny how it can be a small world sometimes.
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I would never have thought to look, but Digikey has them in a wide range of wavelengths and packaging, etc.
Some draw up to an amp each.